Answer:
Transport oxygen.
Explanation:
Red blood cells transport oxygen throughout the body with the help of hemoglobin.
Answer:
polypeptides
Explanation:
Amino acids generally represent the building blocks of proteins. In order words, proteins are polymers of amino acids.
The amino acids in proteins are linked together by peptide bonds. <u>A peptide bond is formed between two amino acids when the amine group of one of the amino acids combines with the carboxylic group of the other with the elimination of water</u>. When the reaction involves multiple amino acids, multiple peptide or polypeptide, also known as protein is formed.
If a cell membrane became impermeable, instead of selectively permeable, the cell would not remain alive, though certain organisms would be able to stay alive longer than others. This is because the cell membrane allows essential molecules and substances such as oxygen into the cell, while allowing harmful substances, like waste, out of the cell.
:)
There is no answer that is right except for C. Natural Selection.
Genetic Recombination doesn't change gene frequency;nor does migration. (Unless it's local)
Mutation could be the answer, but since mutations are too rare to really power Evolution, the only logical answer is Natural Selection.